Discussion Forum

Hello,

I am modeling interstitial blood flow in the tumour tissue surrounded by the normal tissue, which are both assumed to be porous media. So I use Brinkman equation, which consists of momentum and mass balance equations. As there is exchange of blood between interstitium and blood vessels, the source term in mass balance is non-zero. But my question is that does the same source term appear in the momentum equation as well? My bibliography shows that most models just include source term in the continuity equation and not in the momentum equation, as they were implemented in Fluent.

My second question is How to set the continuity boundary conditions (flow and pressure) at the interface between the tumour and normal tissue?
(i) What I have done is to form the geometry as an assembly, thus generating an identical pair automatically. To do so, I have two domains with individual Brinkman equation in each domain. But according to simulation results, this method doesn’t seem to work.
(ii) Alternatively, I formed the geometry as a union, and had one Brinkman equation in both domains, with respective properties, and source terms in each domain. So the interface boundary is treated as an internal boundary, and continuity condition is met by default in Comsol. But the results showed a negative pressure in the proximity of this boundary, which is not reasonable.

Any suggestions on solving these are appreciating. Thank you very much for your help.

Cong